Telephone-exchange system.



E. E. HINRICHSEN. TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED AU6.'2. l9l6.

Patented Apr. 9, 1918,

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EDWARD E. HINRIGHSEN, OF EAST ORANGE, NEW JERSEY, A SSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATIONJOE NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Patented Apr. o, 1918.

Application filed August 2, 1916. Serial No. 112,691.

To all whom it may concern Be it known that I, EDWARD E. HINRICH- SEN, a citizen of the United States, residing at East Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone- Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems in which telephone lines of different character terminating at a central office may be indiscriminately interconnected by means of a universal link circuit.

The object of this invention is to provide such a system by means of which the work of the operators is simplified and the time required for completingconnections between subscribers is reduced.

In accordance with one feature of this invention there is provided in the usual connecting circuit a listening relay which operates automatically to connect an operators telephone set withthe calling line upon the connection of the link or connecting circuit therewith, and is released to disconnect the operators telephone set when connection is made with the called lineregardless of the character of the calling and calledlines.

This invention will be more fully understood from the following description, reference being had to the accompanying drawings, wherein Figure 1 shows an ordinary cord circuit in which the operators telephone set is automatically connected to and disconnected from the talking strands and Fig. 2 shows a modification of the scheme shown in Fig. 1.

In Fig. 1 there is shown an ordinary common battery subscriber line A and a magneto subscribers line B terminating at a central oiiice, at which there is located a universal cord circuit C for interconnecting the subscribers lines. It will be understood that a large number of subscribers lines similar to lines A and B may terminate at the central oifice, but for the sake of simplicity, only the two line are shown. The universal cord circuit C may be used indiscriminately to interconnect two magnetic lines, two common battery lines or a magnetoand a common battery line. Only those portions of the cord circuit C which pertain to the present invention are shown.

The cord circuit C is provided with a dit ferentially wound listening relay 5 having four windings 6, 7, 8 and 9. Winding 6 is connected directly in the answering end 10 of th sleeve strand of the cord circuit in series with the winding of a marginal relay 11, and winding 9 is connected directly in the call ing end of the sleeve strand of the cord circuit in series with the winding of a marginal relay 13. The winding 7 is normally short-circuitedthrough the contact of marglnal relay 13 and the winding 8 is normally short-circuited through the contact of marginal relay 11. The relays l1 and 13 are of the same resistance. findings 6 and 9 are of the same resistance and number of turns, and windings 7 and 8 are of the same resistance and number of turns. Windings 6 and 7 are connected in series aiding and wmdings 8 and 9 are connected in series aiding, while windings 6 and 7 are connected in multiple opposing with respect to windings 8 and 9. The resistance of the sleeve conductors of the common battery lines i low, usually about thirty-seven (37) ohms, while the resistance of the sleeve conductors of the magnetic lines is high, usually about two hundred (200) ohms.

If two magneto lines are to be connected together, the insertion of the answering plug 20 in the jack of the calling magneto line causes the operation of the listening relay 5 and the cut-off relay over a circuit from battery through the contact of relay 13-, winding 6, of relay 5, winding of relay 11, sleeve strand 10, sleeve contacts of the plug 20 and jack of the calling magneto line, and the winding of a cut-ofi relay (similar to cut-ofl relay 21 of line B) to ground. Since relay 11 is marginal, it does not operate when in circuit with a high resistance sleeve of a magneto line. The operation of the listening relay 5 connects the operators telephone set to the talking strands of the cord circuit. Ascertaining that the calling magneto subscriber wishes to be connected with another magneto subscriber, say subscriber B, the operator inserts the calling plug 22 into the jack of B line, thereupon establishing a circuit for winding 9 of the listening relay 5 and the cut-03E relay 21 which may be traced from battery through the contact of relay 11, winding 9, winding of marginal relay 13, sleeve strand 12,- sleeve contacts of the plug 22 and jack 23 and winding of cutoll relay Qlto ground. Relay 13 is marginal and does not operate. Smce the resistance in series with each of the windings 6 and 9' is thesame, and since these windings are of the same number of turns and are. wound in opposition on the same core, the magnetizing effect of one will be neutralized by that of the other and the armatures of the relay will be released, disconnectingithe operators telephone set from the talking strands.

If two common battery lines are to be connected together, the insertion of the answen ing plug 20 into the jack 25 of line A will cause the operation of the listening. relay 5, marginal relay 11 and cut-oll relay 26 over a circuit from battery through the contact of relay 1?), winding 6, winding of relay 11', sleeve strand l0, sleeve contacts of plug 20 and jack 25 and winding of cut-off relay 26 to ground. The operation of marginal relay ll removes the short circuit from winding 8, so that when the calling plug is inserted into the ack of another common battery line, marginal relay 1?) and the cutoff relay of the line will be operated'over a circuit from battery through windings 8- and 9 of relay 5, winding of relay 13, sleeve strand l2, sleeve contacts of plug 22 and jack of the called common battery line and winding of cut-ofl relay thereof to ground.

' The operation of marginal relay 13 removes the short circuit of winding 7 so that the magnetizing efiect of windings 8 and 9 will be neutralized by that of windings 6 and 7 permitting the listening relay to release its armatures. 7

Should it be desired to connect a magneto line with a common battery line, the insertion of the answering plug 20 into the jack of the magneto line causes the operation of the listening relay 5, but not the operation of the marginal relay 11, as before eX plained. Insertion of the calling plug 22 into the jack of the common battery line causes the operation of the marginal relay 13 which removes the short circuit from the winding 7. findings 6 and 7 in series are now opposed to windings, but ducto the high resistanoe ot the sleeve of the magneto line in series with windings (3 and 7, the

amount of current through these two wind ings is less than that through winding 9, which is in series with the low resistance sleeve of the common battery line. However, the number of turns in winding 7 is so proportioned that under the conditions mentioned, thenumber of effective ampere turns of windings 6 and 7 will be equal to that of winding 9, o that the relay 5 will release its armatures.

If a common battery line. is to be connected to with a magneto line, the number of effective ampere turnsfor the differential listening relay 5 will be equalized in a manner similar to that just described, except that the short circuit will be removed from winding 8 instead of winding 7.

In the cord circuit shown in Fig. '2, a ditterential listening relay 5" is provided'with windings 6, 7 S, 9, similar to the windings of the relay 5 shown in Fig. 1. In the relay 5, however, the windings 6 and 7 are normally in series, and S and 9" are normally in series. A marginal relay 11 controls the short-circuiting of winding 7, while a marginal relay 13. controls the short-circuiting ()1 the winding 8. It. is believed that the operation and cooperation of these three relays will be thoroughly understood without any further discussion.

What is claimed is: 7

1f telephone exchange system comprising aplurality of common battery andlocal battery telephone lines, the common batw tery lines having sleeve resistances ditlering in value from that of the local battery lines, a link circuit for interconnecting the lines indiscriminately, an operators telephone set, a differential relay having a winding associated with each end of a strand oilthe linkv circuit and operating when one end of the link circuit. is connected with either a common battery or local battery line to connect the operators telephone set with the line, and means cooperating in one manner with the sleeve resistance of a com monbattery line and in a different manner with the sleeve resistance of a local battery line when the other end of the link circuit is connected therewith to cause the equalization of the ampere turns ofthe windings of the differential relay, therebycausing the release thereof to disconnect the operators telephone set from the line.

2. A telephone exchange system comprising a plurality of common batter 7 and local battery telephone lines, the common battery lines having sleeve resistances differing in value from that of the local battery lines, a link circuit for interconnecting the lines indiscriminately, an operators telephone set, a differential relay having a windingassociated with each end of a strand of the link circuit and operating when one end of the link circuit is connected with either a common battery. or local battery line to connect the operators telephone set with the. line, and a relay cooperating in one mannerwith the sleeve resistance of a common battery line and in a different manner with the sleeve resistance of a local battery line, when the otherend of the link circuit is connected therewith to cause the equalization of the ampere turns of the windingsv of the differential relay, thereby causing the release thereof to disconnect the operators telephone set from the line.

3. A telephone exchange system comprising a plurality of common battery andlocal tcrconnecting the lines indiscriminately, an operators telephone set, a differential listening relay energized upon connection of one end of the link circuit with either a common battery or a local battery line to connect the telephone set with the line and deenergized upon connection of the other end of the link circuit with either a common battery or a local battery line to disconnect the telephone set from the line, a plurality of windings for the listening relay, and means associated with each end of the link circuit and controlled by the connected lines for determining the number of windings effective for controlling the operation of the listening rela 1 47A telephone eXchange system comprising a plurality of common battery and local battery telephone lines, a link circuit for interconnecting the lines indiscriminately, an operators telephone set, a differential listening relay energized upon connection of one end of the link circuit with either a common battery or a local battery line to connect the telephone set with the line and deenergized upon connection of the other end of the link circuit with either a common battery or a local battery line to disconnect the telephone set from the line, a plurality of windings for the listening relay, and a relay associated with each end of the link circuit and controlled by the connected lines for determining the number of windings effective for controlling the operation of the listening relay.

5. A telephone exchange system comprising a plurality of common battery and local battery telephone lines, a link circuit for interconnecting the lines indiscriminately, an operators telephone set, a difierential relay controlling the connection of the operators telephone set with the link circuit, and means associated with each end of the link circuit and controlled by either a common battery or a local battery line upon connection of the link circuit with the lines to equalize the number of ampere turns of the windings of the differential relay.

6. A telephone exchange system comprising a plurality of common battery and local battery telephone lines, a. line signal and a controlling cut-off relay for each line, the resistance of the common battery cut-ofl' relay being dilferent from that of the local battery cut-ofi' relay, a link circuit for interconnecting the lines indiscriminately, an operators telephone set, an energizing circuit for the differential relay established upon the connection of one end of the link circuits with a line ofeither character and including the winding of the cut-0E relay of the engaged line and one winding of the diflerential relay, a deenergizing circuit for the difierential relay established upon the connection of the other end of the link circuit with a line of either character and including the winding of the cut-ofi' relay of the engaged line and the other winding of the diiferential relay, and means governed by and cooperating with the cut-ofi relay of the engaged lines for equalizing the ampere turns of the windings ofthe differential relay.

7 A telephone exchange system comprising a plurality of telephone lines of different character, a universal link circuit for interconnecting the lines, an operators telephone set, a differential relay having a plurality of windings and energized upon connection of one end of the link circuit with a line of either character to connect the operato'rs telephone set with the line, and deenergized upon connection of the other end of the link circuit with a line of either character to disconnect the operators telephone set, and a relay in each end of the link circuit and operating when connection is made with a line of one character and not operating when connection is made with a line of another character to determine the number of the windings effective for energizing and de'elnergizing the differential relay.

In witness whereof, I hereunto subscribe my name this 31st day of July, A. D. 1916.

EDWARD E. HINRIGHSEN.

Copier; of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0." 

